The present invention relates to an automatic clothes dryer having a cool down cycle and in particular relates to an operator preferential adjustment to the cool down cycle.
In automatic clothes dryers it is common practice to have a user select a number of drying features such as, for example, permanent press, normal, fluff, and delicate that control the heat drying cycle of the clothing articles in the dryer and that also control the cool down cycle during which the clothes are allowed to cool down to a safe temperature for the operator to handle and remove articles from the dryer.
In more recent energy efficient clothes dryer controls, microprocessors responsive to thermistors sensing the dryer drum inlet temperature and/or dryer drum outlet temperature automatically control the drying cycle time and energy used depending on various algorithms programmed into the microprocessor and sensory inputs. In some instances the microprocessor calculates the cool down time period. In the cool down cycle, the drum continues to rotate and tumble the clothing and un-heated air is drawn or blown through the drum to cool the clothing. In automatic clothes dryers having a time dependent cool down cycle, the dryer operation is terminated when the time period of the cool down cycle elapses. Alternatively, a default temperature setting is used to terminate the cool down cycle. In this latter cool down control, the outlet thermistor in the cool down cycle continues to sense the dryer air outlet temperature and the microprocessor compares this sensed outlet temperature value with the default temperature setting. When the sensed outlet temperature value reaches the default temperature setting, the cool down cycle is completed.
While the feature of terminating the cool down cycle when the clothes reach a predetermined temperature, usually in the range of 100xc2x0 F. to 120xc2x0 F., depending on the cycle selection, works quite satisfactory, the user of clothes dryer may desire the clothing to be cooler or warmer to his or her touch when removing the clothes from the dryer drum. While this temperature touch sensation is subjective to each user, it is a feature currently not available in present clothes dryers.
It is an object of the present invention to provide a automatic clothes dryer having a cool down cycle where the user may adjust the termination cool down cycle temperature to the user""s preference and touch sensitivity to the warmth of clothing removed from the dryer.
The present invention relates to an automatic clothes dryer having a drying cycle followed by a cool down cycle where the cool down cycle is terminated when the sensed output temperature of the dryer drum falls below a default temperature value preselected or altered by a user.
The present invention relates to an automatic clothes dryer having a drying cycle followed by a cool down cycle. The dryer has a clothes receiving rotatable drum, a blower for circulating air through the drum during the drying cycle and the cool down cycle, and a heater for heating air entering the drum during the drying cycle. The dryer further comprises an air exhaust path along which air is exhausted from the dryer drum and an outlet thermistor positioned in the air exhaust path generating a sensed signal representing the temperature of the air leaving the drum through the air exhaust path. The dryer further comprises a control circuit for terminating the cool down cycle. The control circuit comprises a user variable selection device that is set by the user to represent a user preferred temperature signal. The control circuit includes a comparator having first and second inputs and an output. The first input is connected to the outlet thermistor for receiving the sensed signal representing the temperature of the air leaving the drum. The second input is connected to the user variable selection device for receiving the user preferred temperature signal. The comparator generates at the output a cool down cycle termination signal to end the cool down cycle when the sensed signal favorably compares with the user preferred temperature signal.
The advantage with the present invention resides in the user variable selection device that permits the user to alter or change the value of the preferred temperature signal. That is the user can change the signal to have the clothing articles in the dryer drum either warmer or cooler when the cool down cycle is complete.
It should be understood that the improvement in the present invention relates to the advantageous feature of a user being able to modify the shut down of the dryer so that the heat sensation of the clothing to the user""s touch is to the user""s liking. This is accomplished by the user variable selection device that may be in the form of a rotary dial, a touch pad, or other suitable variable control switches on the control panel that indicate to a user a warmer or cooler final clothes temperature. The selection device permits the user to set the temperature signal within a range defined about a factory default temperature value, which preferably is xc2x15xc2x0 F. about a default temperature of lying in the range of 100xc2x0 F. to 120xc2x0 F. depending on the cycle selection.
It should also be understood that the control circuitry may be a hard wire embodiment of the switches, relays and solenoids, or may be embodied in a microprocessor, or a combination thereof.